Wilhelm lehnek



2 Sheets-Sheet 1.

(No Model.)

W. LEHNER. ELLIPSOGRAPH.

(No Model.) 2 Sheets-Sheet 2.

W. LEHNER.

ELLIPSOGRAPH. No. 520,003. Patented May 15,1894.

flew?" ilNrTEn STATES PATENT OFFICE.

'WILHELM LEHNER, OF MUNICH, GERMANY.

ELLIPSOGRAPH.

SPECIFICATION forming part of LettersPatent No. 520,003, dated May 15,1894.

Application filed July 14, 1893. Serial No. 1:80.503. (No model.)

To aZZ whom it may concern:

'Be it known that I, WILHELM LEHNER, electrical student, of 45 IAmalienstrasse, in the city of Munich, in the Empire of Germany, haveinvented new and useful Improvements in or Connected with Ellipsographs,of which the following is a specification, reference beng had therein tothe accompanying drawlngs.

My invention relates to improvements in or connected with ellipsographsand consists n an ellipsograph whose construction isbased 0n theplanimetrical principle herein described with reference to the diagramFigure 7 in the accompanying drawings.

It the end point Pk of a line P7t,Pg, describes a circle while the otherpoint Pg moves along a straight line G passing through the center of thecircle, the several points of the straight line Pk,-Pg between the twoend points, for instance the point P, will describe ovals. These ovalsbecome ellipses, when, in every position of the line, the point P thatdescribes the oval is moved parallel to the straight line G toward P sothat the lines P0cPy PP and P P 850., remain constant being out by theperpendicular lines from Pit and P to the line G at equal distancesapart.

In the accompanying drawings Fig. 1, is an elevation of an ellipsographconstructed 1n accordance with my invention. Fig. 2, is a plan view ofthe same. Fig. 3, is a section on line 3-3 of Fig. 1. Fig. 4:, is asection on line 4--:t. Fig. 5, is a section on line 55, and Fig. 6, is aplan of the disk a (Figs. 2 and 4t), and Fig. 7 is a diagrammatic Viewlllustrating the construction of the ellipse.

On this principle is based the construction of the ellipsograph formingthe subject of this invention which is illustrated in the accompanyingdrawings.

The main portion of the instrument is formed by a framing which consistsof two end portions a and two side portions 12, and carries in themiddle the elevated longitudinal stirrup bar 0. This bar 0 is perforatedfor the purpose of receiving a crank mechanism which is illustrated insectionin Fig.

5. A crank handle 6 is fixed on the square portion of the spindle orstud z. The lower portion of the pin serves as a guide for the of thespindle or stud z, and can be fixed by means of the set screw 01(Fig.1). On the end of the horizontal arm f isa pin 2 which when thecrank handle is rotated carries one end of a rod .9 round with it in acircle. At its other end the rod 8 moves by means of the sliding piece 9along the stirrup bar 0. Thus the rod 8 corresponds to the line Z shownon (Fig. 7). On sis the movable sliding piece 9" which is capable ofbeing fixed by a set screw and is furnished with the pin h. The movablesliding piece 9 and with it the pin it describes when the crank handleis rotated an oval according to the planimetrical construction. Now thisoval is converted by the ellipsograph forming the subject of this invention into an ellipse with the help of the following parts. The frame1! slides with its guides at (Fig. 4:) along the bars I) which areparallel to the stirrup bar c. The distance P-P Fig. 7, or the distancebetween the perpendiculars from P and P upon Gwhich is a constant, isrepresented in the ellipsograph by the distance of the longitudinalcenters of the two slots 11' and t" which are set or rendered invariableor fixed when the ellipsograph is in use. In one slot 11 the pin 2 movescorrespondingly to Pk (Fig. 7) along an arc of a circle and carries withit the frame '5 and cross bar q withtheir slots v1 and t'" whichcorrespond to the perpendiculars from P70 and P upon G (Fig. 7). Now thesliding piece g which describes the ellipse is fitted in the slot t" sothat it (g') can slide along the cross piece q and the said slidingpiece 9 is provided with the slott (parallel to the elevatedlongitudinal stirrup bar 0) in which the pin h of the movable slidingpiece g works and the said movable sliding piece g is operated by thepin it. The part 9 carries a vertically movable lead pencil-holder whichis weighted with a weight 70 (Fig. 4:). The said lead pencil-holder canbe raised clear of the paper when required and be kept in the raisedposition by the engagement of a nose or catch on in a disk u.

The abscissa produced by the sliding piece g and the point of the leadpencil is fully determined by the position of the pin a (correspondingto the point Pic Fig. 7) and by the constantly preserved distance of thecenters of the two slots 71' and i" from each other and this distancecorresponds to the two perpendlcular lines from Pit and P to the lineGPoc (Fig. 7). Since the ellipse is formed from the oval by the movementof the several points of the latter parallel to G (Fig. 7) thereforeanalogously the sliding piece g is provided with a groove 25 parallel toc in which groove the pin h moves.

The use of the apparatus is as follows: The major and minor axes of theellipse to be described being given, the horizontal arm f is moved untilthe distance of two markers or indicating lines 0 and 0' from each other1s equal to half the major axis (the markers 0 0' having been moved outan equal distance from d and z) and the arm is then fixed by such thatthe horizontal arm f is at right angles with the stirrup bar a; then thecross arm qand the sliding piece 9' are moved until the point of thelead pencil comes over a line drawn parallel to the major axis throughthe end point of the half of the minor axis. Then the cross arm q andthe movable sliding piece 9" are fixed by means of the set screws; thesliding clamp r is removed from the hand crank e and the handle of thehand crank e is moved round in a circle, whereupon the point of the leadpencil describes the mathematically exact ellipse required.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is-

An ellipsograph comprising the main frame, a supplemental frame slidingthereon, a central bridge piece 0, having vertical crank shaft WILHELMLEHNER.

Witnesses:

O'rro BAOHMAYR, EMIL STAIGEY.

